I have a betta fish that I got about a week & a half ago, and I'm worried that something's wrong with his gills. Last night after he flared them out, these marks on them looked bright red. Now they don't look quite so red, but I don't think they look normal, either. I bought some bettafix today, but I'm not sure if I should use it. I really don't want my betta to die. What should I do?